03-09-2011, 12:10 PM
This season's cold and record snowfall make it hard for wildlife, but for fish, mussels, plants and other aquatic life, but on some water bodies a severe winter can be fatal. As ponds and lakes freeze over and snowfall piles up on the ice, the fish and their fates are sealed, literally, under a layer of ice. Winter fish kills (or winterkill) are the result of significant decline in oxygen levels in a water body during a long period of ice and snow cover. Snow-covered ice blocks sunlight, greatly decreasing the amount of oxygen plants and algae once produced. Oxygen levels drop further because all aquatic life, including the fish, are consuming what little oxygen is left in the water. In these conditions, a complete winterkill can occur. This condition is natural and rarely the result of pollution such as illegal dumping, sewage or a chemical spill.
Reports of strong "rotten egg" odors are generally the first clue that a waterbody is experiencing anoxia (lack of oxygen). The odor is hydrogen sulfide gas which is a natural by-product occurring in lakes and ponds with low amounts of dissolved oxygen. Ice anglers are often the first to notice these conditions and observe distressed fish gasping for air at holes in the ice or live baitfish dying on fishing lines. The Division of Fisheries and Wildlife (DFW) has recently received several calls from ice fishermen reporting this phenomenon on some shallow, weed-choked lakes. DFW fisheries biologists routinely find low dissolved oxygen levels in these types of habitats; prime candidates for winterkill. Most of the time, the results of winterkill are not seen until spring when the ice melts and citizens discover dead fish on the bottom of the pond or floating at the surface.
To report a fish kill Monday through Friday between 8:00 am and 4:30 PM, contact Richard Hartley at (508) 389-6330. After normal business hours or on holidays and weekends, contact the Environmental Police Radio Room at (800)-632-8075. For more information about winterkill, go to: www.mass.gov/dfwele/dfw/fisheries/fish_kills.htm.
Reports of strong "rotten egg" odors are generally the first clue that a waterbody is experiencing anoxia (lack of oxygen). The odor is hydrogen sulfide gas which is a natural by-product occurring in lakes and ponds with low amounts of dissolved oxygen. Ice anglers are often the first to notice these conditions and observe distressed fish gasping for air at holes in the ice or live baitfish dying on fishing lines. The Division of Fisheries and Wildlife (DFW) has recently received several calls from ice fishermen reporting this phenomenon on some shallow, weed-choked lakes. DFW fisheries biologists routinely find low dissolved oxygen levels in these types of habitats; prime candidates for winterkill. Most of the time, the results of winterkill are not seen until spring when the ice melts and citizens discover dead fish on the bottom of the pond or floating at the surface.
To report a fish kill Monday through Friday between 8:00 am and 4:30 PM, contact Richard Hartley at (508) 389-6330. After normal business hours or on holidays and weekends, contact the Environmental Police Radio Room at (800)-632-8075. For more information about winterkill, go to: www.mass.gov/dfwele/dfw/fisheries/fish_kills.htm.